Pressure switch for A/I kit?

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03-24-08 | 12:20 PM

#26

Richard L

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Joined: Sep 2006

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From: uk

Ian,

The object of the exercise was not about spray pattern. There were plenty of water sprayed. It was about the accuracy of a delivery based on a pump speed controlled system.

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03-24-08 | 01:37 PM

#27

Richard L

Senior Member

Joined: Sep 2006

Posts: 402

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From: uk

Quote:

Originally Posted by slo

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PWM ing the pump with the pressure switch is no different than PWM ing with a controller, except that the freq and pulse width would be continuously variable. At its max flow with the freq at its highest it would still be a fairly low freq.

If the pump doesn't have a problem PWM from a controller then I would say I can't see it being a problem from a switch.

Also the pressure fluctuations as seen on a gauge where small like a 5 PSI sweep at the highest.

I have found the video that show the pressure spikes on a "progressive pump speed" system. The duty cycle of the controller is manually increased. The gauge is undamped. Look at the moment when the PWM frequency hits the resonance of the natural frequency of the motor winding.

Even when it has hit the resonance frequency, the pressure ripple is still very high. Those spikes will trigger the pressures switch that regulates the line pressure.